Leakage current conduction of pulsed excimer laser ablated BaBi₂Nb₂O₉ thin films

Abstract

The leakage current behavior of the BaBi₂Nb₂O₉ (BBN) thin films was investigated over a wide range of temperatures. The current density, calculated from current-voltage (I-V) characteristics at room temperature, was 4.02× 10^-9A/cm² at an electric field of 3× 10⁵V/m. The I-V characteristics of the films showed ohmic behavior for electric field strength lower than 1 MV/m. Nonlinearity in the current density-voltage (J-V) behavior was observed at an electric field above 1 MV/m. Different conduction mechanisms were brought into picture to explain the I-V characteristics of BBN thin films. The J-V behavior of BBN thin films was found to follow the Lampert's theory of space charge limited conduction in an insulator with traps. Three different regions, i.e., ohmic, trap filled limited, Child's law were explicitly observed in J-V characteristics. The activation energies in the ohmic region calculated from the Arrhenius plot were 0.46, 0.48, and 0.51 eV, respectively. These energies were attributed to the shallow traps, distributed near the conduction band edge in the forbidden gap of the materials.